Mac Outlook version 15.28 or later is required. Requirements for Skype for Business and Outlook integration on Mac: You can download these updates at Updates for Skype for Business Server 2015 and Updates for Lync Server 2013.

After updating to builds 9317.272 or 8309.973 or later, Mobility enablement will no longer be required. Without Skype for Business Server 2015 CU4 (build 9319.272 or later) or Lync Server 2013 CU8 HF1 (build 8309.973 or later), Skype for Business on Mac requires Mobility enablement on the server side.

Important: Users will not be able to dial 911 until the CU4 server update is applied.